It is known in the field of aeronautics that rotary structural elements and wing-structure elements are subjected to a high risk of impact from birds, hail, blocks of ice, stones or even pieces of tire or other hard debris encountered by the aircraft in flight, during landing or during takeoff.
The rotary elements associated with the engine or with the mobile wing structure of an aircraft, for example the fans or fan elements such as the vanes and blades of an aircraft, are particularly exposed to dynamic contact generated by birds or other debris encountered by the aircraft. In particular, the composite blades of certain engines are particularly vulnerable. Now, these impacts are very high energy impacts because the impact speed may be as high as 100 m/s. They may therefore prove particularly injurious to the rotary structural elements and, in extreme cases, cause the aircraft to crash.
In the case of aircraft engines with contrarotating fans and rear drive, the engines are generally situated near to the fuselage. Since this type of engine is generally unducted, impact on the rotary elements of the engine may cause an engine element or part of this engine element to detach, with all the consequences that that has for the flight of the aircraft. There is therefore, upon an impact, a high risk of partial or complete detachment of a rotary element of the engine and of a chain reaction of consequences as this detached element re-impacts another rotary element of the engine or an opposite engine, the impact speed for impact on a rear fuselage element then being estimated at 300 m/s.
Aeronautical manufacturers are therefore seeking to minimize as far as possible any partial or complete loss of rotary elements from the engines in the event of an impact by creating rotary structural elements that are able to withstand these impacts.